What to Do When Rearview Mirrors Fog Up After Rain?
3 Answers
When the rearview mirrors fog up, you can turn on the rearview mirror heating system to defog them. Cars equipped with a rearview mirror heating system have electric heating wires inside the mirror lenses. When the mirror heating is turned on, these wires will generate heat through electrical current.
I make it a habit to apply anti-fog spray to the side mirrors before the rainy season starts - it lasts for several days. I always keep a dry towel in the car; when fog appears, I just pull over and wipe them quickly. For highway driving, I recommend using the hot air blower on the windshield, which also helps defog the side mirrors. By the way, my car doesn't have heated mirrors, so I installed rain deflectors - they work well in light rain, but heavy rain still requires anti-fog spray. Never try to wipe the mirrors while driving - it's too dangerous. Safety is far more important than saving time - pull over when needed. Keeping mirrors clean is crucial; I always ask the car wash attendants to thoroughly clean the mirror surfaces.
When I find the rearview mirror fogging up, I first turn on the air conditioning in dehumidification mode and adjust the airflow to the windshield position. Cracking the window slightly helps balance the temperature difference inside and outside, making the fog dissipate faster. Usually, I use a mixture of dish soap and water as a simple anti-fog solution, which works quite well. Once on the highway when sudden fogging occurred, I immediately slowed down, turned on the hazard lights, and looked for a service area to handle the situation. I recommend keeping anti-fog wipes in the car—one wipe can last half a day. Remember to clean the rearview mirror regularly, as oil buildup makes it more prone to fogging. Applying a rain-repellent film offers longer-lasting effects, but be sure to have it installed by a professional.
